I have 4 bungied (if thats a word) in the front of my antec 900, I did have to do some drilling to get the holes where I wanted away from the from fans.
I would say defiantly use budgie over elastic as elastic isn't designed to be left stressed, a least I was told this and it seems to make sense.
Temps are lower than when I had 1500rpm fans (6 x 800rmp now), they've gone from around 34c to 30c now Ive done my silencing.